It is known to produce identity cards with an image of the intended card holder. The image allows visual identification of the card holder. Even with a protective overcoat over the image, it is possible to remove the photo pigments that form the image using a combination of chemicals and acute abrasives. The removed image can then be substituted with a new image and the card used fraudulently. Efforts have been devised to prevent tampering of the image on an identity card. For example, see U.S. Pat. Nos. 5,350,198; 5,435,599; 5,774,168; 6,633,321; and 6,867,167 (EP 1 187 727).
However, continued improvements are necessary to prevent tampering of images on identification documents.